Re-enable BWC tests and adjust versions after #77695 backport to 7.x (#78753)

build.gradle

@@ -140,9 +140,9 @@ tasks.register("verifyVersions") {
  * after the backport of the backcompat code is complete.
  */
 
-boolean bwc_tests_enabled = false
+boolean bwc_tests_enabled = true
 // place a PR link here when committing bwc changes:
-String bwc_tests_disabled_issue = "https://github.com/elastic/elasticsearch/pull/77695"
+String bwc_tests_disabled_issue = ""
 /*
  * FIPS 140-2 behavior was fixed in 7.11.0. Before that there is no way to run elasticsearch in a
  * JVM that is properly configured to be in fips mode with BCFIPS. For now we need to disable

server/src/main/java/org/elasticsearch/index/store/StoreFileMetadata.java

@@ -28,7 +28,7 @@ import java.util.Objects;
 public class StoreFileMetadata implements Writeable {
 
     public static final BytesRef UNAVAILABLE_WRITER_UUID = new BytesRef();
-    private static final org.elasticsearch.Version WRITER_UUID_MIN_VERSION = org.elasticsearch.Version.V_8_0_0;
+    private static final org.elasticsearch.Version WRITER_UUID_MIN_VERSION = org.elasticsearch.Version.V_7_16_0;
 
     private final String name;